The present invention relates to rotary mowers for cutting vegetation including grass, brush and the like, and more particularly to a rotary ditch mower having a main body and extension wings or side sections supporting a number of cutting blades. The main body and extension wings are supported by contour following ground wheels and the main body also foldably supports the extension wings which may be inclined relative to the main body. The mower is also provided with a hitch pole for pull behind connection with a tractor and an articulation mechanism of the main body and extension wings for adjustment of cutting height over varying terrain during cutting operations as well as for raising the extension wings to a transport position and for raising the mower to a substantially vertical position, i.e., the main body and extension wings raised perpendicular with respect to the ground to facilitate servicing and maintenance of the mower.
Pull behind rotary mowers can be generally classified into two types, finishing mowers and ditch mowers. A finishing mower, has separate distinct cutting sections with each section having ground contouring wheels. A top frame couples all of the panels together and controls cutting height and transportation.
These mowers are typically used on golf courses. The second class of mower, called a rotary cutter or ditch mower, is a unibody construction with the panels joined to the main center section by long hinges. The frame to control transportation and cutting height is typically incorporated into the cutting panels.
Rotary mowers for cutting vegetation in ditches are usually comprised of three five-foot wide panels supported by ground wheels that follow the contours of the ditch. The frame is made up of a linkage that keeps the mower parallel with the ground. Mowers travel at slow speeds (two to three mph) and, cut close to the ground with hardened steel blades rotating at speeds of up to and around 180 mph. They are designed to cut through debris-laden ditches and have long operating hours resulting in high maintenance requirements. One common problem is changing blades or making repairs to the center section where it is necessary to crawl underneath. The wing blades and wing panels however can usually be easily repaired as the wings fold up vertically. Priefert, U.S. Pat. No. 4,858,417 discloses a mower with adjustable extension wings and teaches how to perform a center section rotation to a vertical maintenance position through a complicated sequence of manual unlocking and locking mechanical procedures. Therefore it is imperative that the mowers be designed with as simple and maintenance free a mechanical operating system as functionally possible.
Rotary mowers must be generally serviced with each use. All U-joints, pivot pins and wear points are greased, and debris that collects on the top deck is brushed off on a daily basis. Cleaning is a common problem due to the volume of debris that collects on the top deck and clippings on the lower deck. Mower construction generally consists of a flat sheet of steel with hollow structural members (structural tubing) welded to it for rigidity. The pockets and corners created by this typical mower construction not only make it difficult to clean, but they collect water that causes rusting. Previous mower deck designs have strength and moments of inertia which vary dramatically. Areas are strong where there is a structural tube welded to the deck and areas in between the tubing are very weak, as strength is determined by the deck thickness alone. Some previous mower decks disclose a double deck design that reduces water pooling and debris. However these double deck designs consist of a flat bottom sheet and a sloped top sheet welded to structural tubing frame.
The present invention relates to a mower having a simple mechanical system for rotating the center section substantially to a vertical position to allow the operator to safely change blades, make repairs, clean debris and inspect the center section. The linkage and mechanics of the present invention are simple and cost effective. Not only does one set of hydraulic cylinders act as a solid link bar in a parallel linkage design, but also the same set of hydraulic cylinders when actuated will fold the mower forward into a vertical position to substantially expose the center section underside. This system has a minimum number of linkage pivot points to limit the potential repair areas. The present invention also relates to a variety of similar linkages that will produce the same net result. The present invention also shows a method of incorporating xe2x80x9croll up skid padsxe2x80x9d into a linkage member.
A second improvement consists of a two tiered top and bottom deck. The top deck consists of xe2x80x9cUxe2x80x9d shaped panels that when assembled together with a flat bottom deck make up a contoured unibody frame having a contoured or tapered top deck. The top and bottom deck when assembled together are separated by support members of the xe2x80x9cUxe2x80x9d shaped panels creating a unibody type frame having spaces defined between the top and bottom decks and a high strength to weight ratio. Damage to the deck from rocks, stumps or other flying debris is thus limited to the bottom or lower deck. This allows the top or upper deck to be free of damage thereby enhancing the cosmetic qualities of the mower.
This compartmental structure of the deck section is much stronger than current designs as it accounts for the directly proportional increase in the moment of inertia relative to the moment. For example, where the moment is greatest in the center of the deck the moment of inertia is correspondingly high and therefore the deepest portion of the deck is designed. As the moment decreases towards the edges of each deck section, the moment of inertia is reduced accordingly by decreasing the spacing between the top and bottom decks. This tapered design also facilitates a reduction in the extra material and weight at the tapered ends of each deck section where the moment is lowest.
Wherefore, it is an object of the present invention to overcome the above mentioned shortcomings and drawbacks associated with the prior art.
Another object of the present invention is to provide a less complicated and more durable mechanical system for articulation of the mower adjustment for cutting height, repair and maintenance configuration and extension wing inclination.
A further object of the present invention is to provide the improved mechanical system with a range of motion articulating the center section of the mower from an operable substantially horizontal cutting position to a substantially vertical maintenance and repair position.
Yet another object of the present invention is to provide an upper and a lower deck to the mower body having greater structural integrity and improved moment of inertia and an exterior profile for facilitating the cleaning and shedding of debris.
A still further object of the present invention is to provide a double deck mower such that damage is limited to the underlying lowerdeck and is not visible through the top deck spaced therefrom.
The present invention also relates to a rotary mower for use in combination with a motorized tractor having an attachment point for releasably connecting the rotary mower to the tractor, the rotary mower comprising a main body having a front end defining a front support pivot and a rear end defining at least a rear support pivot, a hitch pole connected to and extending between the front support pivot and the attachment point of the tractor for pivotably supporting the front end of the main body, at least a pair of ground wheels rotatably connected to a first end of a ground wheel support arm connected to the rear support pivot for pivotably supporting the rear end of the main body, and a first variable length linkage substantially controlling pivoting of the ground wheel support arm about the rear support pivot and a second variable length linkage extending between the hitch pole and the rear support pivot for adjustably controlling a cutting height of the mower and maintaining the main body of the rotary mower substantially parallel with respect to the ground.
The present invention also relates to a method of providing a maintenance and repair position for a rotary mower used in combination with a motorized tractor, the method comprising the steps of building a main body having a front end defining a front support pivot and a rear end defining at least a rear support pivot, connecting a hitch pole between the front support pivot and the attachment point of the tractor for pivotably supporting the front end of the main body, rotatably connecting at least a pair of ground wheels to a first end of a ground wheel support arm connected to the rear support pivot for pivotably supporting the rear end of the main body, and controlling a cutting height of the mower and maintaining the main body of the rotary mower substantially parallel with respect to the ground by pivoting of the ground wheel support arm about the rear support pivot via a first variable length linkage connected between the rear support pivot and the main body and a second variable length linkage extending between the hitch pole and the rear support pivot.